You wear sunscreen every day, don’t smoke, and spare no expense on skin creams and potions. But despite your best intentions, you may still be making errors that can lead to premature aging. Here are five common skincare blunders to avoid.

1. Over exfoliatingPeople with dry skin often think exfoliating can help by sloughing away flakes and dead skin cells. But over exfoliation can make dry skin worse by impairing your skin’s ability to hold onto water, making it look dull, lifeless and older. I’ve seen patients exfoliate so much they get a rash that feels like sandpaper!

2. Using the same moisturizer year-roundSome skin types are oily in summer and dry in winter. This is because there is less water in the air in the winter and skin can easily become dehydrated. If you have oily skin, don’t assume you should use an oil-free moisturizer all year–or that you can go without. Instead, use a serum or lotion when your skin is oily and switch to a richer cream when it’s dry. Many companies include these options in their lines–try antioxidant-rich Topix Replenix Serum CF for summer and Topix Replenix Cream CF when the weather gets colder.

3. Using a harsh cleanserPeople love the tight, tingly feeling they get after using foaming cleansers and bar soaps, but that feeling just means your natural lipids have been stripped away, leaving your complexion parched and more prone to premature wrinkling. Instead, I recommend an oil-based cleanser like Shu Uemura High Performance Balancing Cleansing Oil. If you can’t bear putting oil on your face, you can always use good old Cetaphil.

4. Going greenI love organic products, but when it comes to retinoids and sunscreen, nothing can replace a chemical formula. There’s no natural alternative to retinoids like Differin and Atralin, and they’re the only products proven to diminish existing wrinkles. Organic sunscreens are just not as effective as their chemical counterparts, especially if you’re going to be in the sun for prolonged periods. So my advice is to use an organic cleanser and moisturizer, but until better sunscreens and anti-aging treatments hit the market, stick with the nonorganic for now.

5. Mixing the wrong ingredientsSome ingredients are not compatible. For example, neither retinoids nor hydroquinone should be used in combination with glycolic acid, which renders them inactive. And you can only use hydroquinone and retinoids together if they’re in a specially formulated product like Tri-Luma. All of these ingredients fight signs of aging and sun damage–but you have to use them correctly to get results.